Gold-colored organic crystals formed from an azobenzene derivative

Akiko Matsumoto, Maho Kawaharazuka, Yutaka Takahashi, Norio Yoshino, Takeshi Kawai, Yukishige Kondo

研究成果: Article査読

13 被引用数 (Scopus)


The azobenzene derivative 4,4′-bis{1-[2-(N,N-dimethylamino)]ethoxy}azobenzene has been found to form gold-colored plate-like crystals. The thin film obtained by accumulating the crystals has a maximum specular reflectance of ca. 15% for visible light. To investigate the structure of the gold-colored crystals, UV-vis, X-ray diffraction (XRD), and IR analyses were performed. UV-vis measurements show that the molecules in the crystal produce J-aggregates. Furthermore, XRD measurements estimated the long-range d-spacing for the crystal as 1.51 nm. These results indicate that the azobenzene moieties are oriented diagonally against the crystal surfaces. When the crystals are placed in a desiccator (humidity 40%) for 1 d, their color changes from gold to yellow. IR measurements show that the gold-colored crystals contain crystallized water, while there are no water molecules in the yellow crystals, in which the structure of the J-aggregates is disrupted. These results show that the crystallized water molecules are essential for the formation of the J-aggregates and the resultant gold luster.

ジャーナルJournal of oleo science
出版ステータスPublished - 2010 2 3

ASJC Scopus subject areas

  • 化学 (全般)
  • 化学工学(全般)


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